Printing telegraph apparatus



July 16, 1946. W.IJ. ZENNER 2,404,339

PRINTING TELEGRAPH APPARATUS Filed Feb. 28, 1945 2 Sheets-Sheet l INVENTOR I WALTER .1 ZENNER z Ww ATTORNEY Filed Feb. 28, 1945 2 Sheets-Sheet 2 INVENTOR WALTER J. ZENNER Patented July 16, 1946 UNITED STATES PATENT OFFICE;-

PRINTING TELEGRAPH APPARATUS Walter J. Zenner, Des Plaines, Ill-., assignor t Teletype Corporation, Chicago, 111., a corporation of Delaware Application February 28, 1945,Serial No. 580,154;

This invention pertains to printing telegraph apparatus and more particularly to transmitter control mechanism.

The primary object of the present invention is to provide a device for automatically arresb ing transmission of signals fromatransmitter distributor upon the opening of the signal line circuit.

Another object of the invention is to provide a break-lock mechanism which is effective upon the opening or breaking of the signal line circult to arrest transmission of code signals-from the transmitter distributor apparatus.

Specifically, the invention is applicable to communicating apparatus of thecombinationsende ing-receiving type, which is designed for interchanging messages between two or more points, and which consists of a tape transmitting unit and a combination printer-reperforator unit In handling telegraph communications it sometimes becomes necessary for the operator at the receiving station to communicate with the operator at the sending station, and it is often very important that the receiving operator be enabled to interrupt the operation of the transmitting apparatus. This interruption by the receiving operator is known in telegraphy as br'eakingor operating break-in signals.

In the arrangement according to thepresent invention, a perforated tape is prepared upon a reperfor'ator, after which the tape is directed to a tape transmitter distributor, from which the message perforated in-thetape is transmitted over 11 Claims. (Cl. 178,-:17)

unit which is designated generall by the numeral ll receives the tape l2 from a tape perforating apparatus l3, many types of which are well known in the art. ,The tape sensing unit and transmitting unit. are describedonly to an extent necessary to understand the present in vention and may be understood moreyfullyv by referring to Bulletin 141, issued in March, 1942, by the Teletype Corporation, Chicago, Illinois, wherein they are described substantially.

The tape l2 passes 'over' a guide roller l4, moves downwardly and under ataut-tape roller l6 which will be mentioned later, and forms in a loop'and passes over a' guide roller II which. is in a horizontal plane with the previouslymenti'oned guide rollerv M. The taut-itape roller [6 iss'upported in two slotted guides 18 and has an out-.

wardly extending'arm t9 whichaco'ntrols' an electrical contact pair 2|, as will be hereinafter described. The tape I2 then passes over a sprock et-wheel 22' which is fastened securely to a shaft feed the tape through the sensing mechanism. The shaft 23 has a ratchet 24 secured to one end thereof by means of which the tapefeedoperathe signal line to the remotely located printer. I

If the receiving operator is desirous of interrupt ing this transmission; he will open or break the line, so that a break-lock mechanism in said transmitter will be operated to stop transmission and to simultaneously close an alarm circuit,

whereby the sending operator is apprised of the interruption so that he can thereby prepare his apparatus for reception of the urgent message,

and thereafter prepare hismachine for retransmission of the received message, the interrupted message, or any other intelligence. I

A more complete understanding of. the-foregoing and otherobjects and features-of thepr'esent invention may be had from the following description when taken in conjunction" withthe' accompanyingdrawings-in which Fig. 1- is-a schematic arrangement of one em'- bodiment of the presentinvention; and

Fig. 2 is aschematic arrangement of a modifi'ed* f mm of the invention.

Having reference to Fig. 1, the tape'sensing tion is effected, aswill be later explained.

Immediately after the tape [2 passes from the sprocket 22. it passes over a set of five contact levers 26 each of which hasatape sensing pin 21 extending upwardly from its forward end. The tape sensing pins 21 are adapted under certain operating conditions .to' probe upwardly to' sense the tape in order to determine whether the particular code signal being sensed is comprised of marking or spacing. impulses, in a manner well Positioned approximately below the shaft 28 is J a contact lever ball 34 which is immediatelyto the right of the downwardly extending arms3l ofrthe contact levers-25 and extends across all; of; the arms 3|. Thebail 34, mounted pivotally' on a pivot shaft 36, has a downwardly extending lug 31.;

Also mounted pivotally on the shaft 28 is a feed lever 38 which'has a leftwardly extending arm 39 and a downwardly extending arm 4|. A

1 spring 42 is connected to the arm 39 and tends to pivot the feed lever 38 in a counterclockwise direction about shaft 28, as viewed in Fig. 1. The

feed lever 38 has a feed pawl 43 mounted pivotally at its rightward extremity, which has a spring 44 connected 'to a downwardly extending lu thereon and which tends to pivotthe feed pawlin a clockwise direction.

The feed pawl 43 is situated adjacent to the"- ratchet wheel 24 and cooperates therewith during certain operating conditions to cause the tape I2 1 to be fed forwardly. The bail 34, described pref viously as extending across the downwardly ex-' tending arm 3| of the contact levers 26, also extends across the downwardly extending 5311111 4 of the feed lever 38.

Situated immediately to the left of the slots 33 at the extremities of the rearwardly extending arms 29. of the contact levers 26 are a seriesof. five contact .arms46, one individual to each ,con-J tact arm 26, which are mounted pivotally on an electrical conductor shaft 4'I.v The right-hand ends of the contact arms 46 which cooperate with the slots 33: are insulated, whereas the remaining portions'of the contact arms are electrical conductors. The opposite ends of the contact arms 46, remotefrom'theinsulated portion cooperating with the slots 33, form a movable tongue to cooperate with an upper electrical spring contact 48 or a lower electrical spring contact '49. Thus,

transmitter operating lever I6 pivotally mounted on a stud TI. The opposite end of the transmitting operating lever I6 has an upwardly extending portion I8 which has an adjusting screw 19 passing therethrough. The adjusting screw I9 is immediately adjacent to the downwardly extending arm 31 of the contact lever bail 34,

previously described, and'cooperates therewith ina manner to be explained.

'The various parts which have been described above areall well known equipment and are substantially described in the above-mentioned bulletin issued'by' the Teletype Corporation. However, it isfneces'sary to describe them herein inasmuch 'asthe'y form part of the present invention,

. as will now be'set forth.

To. achieve the objects of the present invention I there are also mounted on shaft 58 timing cams depending upon the position of the contact arms 46 an-electricalcontact will be made with either. the 'upper spring contact 48 or the lower spring. contact 49, in a manner to be hereinafter'dee scribed; 1

The transmitting unit comprises. a commutator 5| formed with five equal size segments 52,

BI and 82 which, upon the occurrence of a break in the line, for example, upon'the opening of a switch I39 at the remote station I38, control-the stopping of the transmitter in such a manner to insure the completion of the code signal combinationbeing then transmitted; cooperatively as sociated with cam 8| is one end of a lever 83 pivotally mounted on a pivot 84. Lever '83is nor;

mally biased in a clockwise direction by a spring 86tc maintain its left'end (Fig. 1) in contactual relation with the periphery of cam 8|. The opposite end of lever 83 provides an armature for a magnet 81 suitably mounted in the transmitter apparatus. J 3 4 Lever 83 is provided, near its left end, with a slot 88 which'accommodates slidablvtherein a thereon, each of, which is assigned to one impulsev of'the well-known Baudot five unit code. Two

other segments are provided on the commutator face other than the five segments 52, one of which,

53,: is assigned to the stop interval while the other, 54,'is assigned to the start interval. 'Thus,

the=transmitting apparatus is of the start-stop type, the operation of which is well known.v A;

collectorring 56 is provided which is formed in a complete circleconcentric to the ring of segments and which is electrically connected successively: therewith by means of a distributor brush 511 whichismounted securely to a distributor shaft 58 to rotate therewith.

A motor 59 is provided having a worm 6| on the motor shaft 69 which cooperates with and continuously drives a gear wheel 62 positioned about the distributor 58; The distributor'shaft is, in turn, driven through a friction clutch 63 cooperating with gear 62 in a well-known manner} A switch 64 is provided which completes an electrical circuit from an alternating current source to drive the motor 59; obviously, a direct current source may also be used. 8

Positioned securely to the distributor shaft 58 is a disc 66 which has a stop lug 61 extending therefrom. The stop lug 61 engages, during certain periods of operation, with the end of a-stop arm 68, which is pivotally mounted on a shaft I9 and which is normally biased in a counterclockwise direction into engagement with the stop lug 61 by means of a spring II. The opposite end of, the-stop arm 68 forms an armature for a mag- An operating cam 13 is also secured to the dis:

tributor' shaft 58 and cooperates with a cam follower roller 14 which forms one end of a operation of the motor. 59g-whichresultsin rota-.

tion of the worm 6|, on the motor shaft and a consequent rotationjof the gear 62' about the dis-1 slidable' member 89. Member 89 is provided with a shoulderedp'ortion 9| having astep or shoulder" 92 which cooperates under certain operating conditions, presently described, with the right, end of slot 88. Member 89 is 'slidably supported by a bracket 93, and is further provided with a laterally directed shoulder 94 which abuts against bracket 93 when slide member 89 is biased rightwardly by a spring 95 and acts as a limiting stop for the rightward movement of -member 89, as well as a pivot point, as will presently appear. Attached to the right end of slide member 189 is a vertically directed stud 96 whichcooperates with the insulated end 91 of 'a contaot'bank 98 com-. prising a normally closed contact pair 99 and a normally open contact pair I9I. I Theleft-hand end of slide 89 (as viewed in Fig.

1) cooperates with the vertically extending portion I92 of arm I93 oflever I94pivotally mounted on 'a pivot I95. Lever I94 is provided with a cam follower arm I96 which cooperates with the periphery of cam 82. A spring I91 normally biases lever I94in a counterclockwise direction to bring arm I96 against the periphery of cam 82.; Lever I94 is also provided with a'downwardly directed portion I98 which cooperates with a normally closed contactpair I99.

The operation of the device according ,to, the present invention and-its cooperation with the.

tape sensing and transmitting apparatus, and the electrical circuits therefonwill now be described.

Upon the manual closing of switch 642. circuit is completed from; the current source to cause the tributor shaft 58. 7 However, atethisgtimejthe distributor shaft 58 will not rotate,inasmuchl asthe' stoparm'68 is-engaging the stop-lug" 6I and preventing rotation thereof. Suchnon-rotation of v 8 the distributor shaft 581s possible because of the friction clutch 63. The distributor brush is at this point on the stop segment 53 of the commutator 5I which is customary in start-stop telegraphy. Upon the manual closure of switch I29, assuming that there is suflicient tape I2 in loop I30 to allow the taut-tape roller I6 to be in a downward position with its arm I9 closing the contact pair 2|, potential will be supplied. from grounded battery I3I through the switch I29, through the contact pair 2| which is closed, over conductor I32, through, normally closed contact pair 99, over conductor I33 and through winding of magnet 12 to ground.

Magnet 12 will upon its energization, cause lever 88 to rotate about its pivot against the action of spring II toremove the extremity of its rightward arm from blocking engagement With stop lug 61 on stop disc 66, thus initiating rotation of shaft 58 and the several elements attached thereto. Cam 13 upon rotating causes lever 15 to oscillate (follower roller 14 being held against cam 13 by springs 32) to in turn impart oscillation to ball 34. As the bail 34 oscillates, t he sensing levers 26'are cyclically actuated to sense the code combinations appearing in the tape I2. The setting of the levers 26 permutably in accordance with code perforations sensed in thetape is transferred to the contact 48 and 49 through them;- strumentality of rockers 46.

When the shaft 58 is in its stop position, as shown in Fig. 1, the distributor brush 51 is on the stop segment 53 of the commutator 5| which is customary in start-stop telegraphy. During this condition of operation the line circuit is completed from ground, through shaft 41, over conductor I34, then either through the winding of magnet '81 or through shunting contacts I09 (depending upon the condition of operation), then over conductor I35, through segment 53, over brush arm 51, through ring 56, over line conductor I36, through the receiving magnet I31 of remote station I38, through switch I39 and to grounded battery I4I. As the brush arm 51 rotates during signal transmission, it traverses in turn the start segment 54 and the code impulse segments 52, completing it code cycle by again contacting the stop segment 53.v The segments 52 are connected to the contacts 48, so that as the contacts 48 or 49 are closed simultaneously during each sensing operation according to the code combination sensed, the impulses are transmitted over the line conductor, to tation I38, sequentially.

Cams BI and 82 are so conformed with notches 85 and 90, respectively, thatmagnet 81 is energized during substantially the latter half of the stop impulse and short circuited through closed contact pair I09 during the remainder of the signal cycle and in the stop position of the transmitter distributor, which occurs during the first portion of the stop segment 53. Thu in the case of several transmitter distributors connected in the line with but one distributor transmitting, the inductance and resistance of the magnets 81 (or magnets I89. in Fig. 2) of the units not transmitting will not be reflected in the line or local circuit as the case may be. Also, in the case of a single transmitter distributor in the line in the stop position or transmitting (when it is desired to prevent the transmitter from responding to a break signal) its break-lock magnet is not in the line or local circuit. Of course, the cam notches could be positioned so that the magnet 81 would be energized during the first portion of the stop segment, but for purposesof the present disclosure-the timing has been chosenso that the magnet 81 is energized immediately afterthe initiation of thesignal cycle. Moreover; if the line circuit is opened 0r fbroken at switch I39 or any other point during the transmission of a code signal, thebre ak will not be effective to stop the operation of the transmitter until the instant codesignal (signal being transmitted) has been completely transmitted, as will presently appear.

While shaft 58 is-rotating continuously during normal transmission and the notch in cam 8I passes the left, end of lever 83 cyclically, the'end of lever 83 will not fall 'into notch 85 because at that time (which is during the stop period) the contact pair I09jopens, due to coacticnbetween arm I06 and notch 90, to remove the shunt around magnet 81, thus permitting magnet 81 to operate to hold lever 83 in its counterclockwise position. However, if a break occurs in the line circuit, thus causing the line to be opened, themagnet 81 will not become energized during the stop period, when contact pair I09 is opened, as no battery will be applied from distant station I38, so that then the lever 83 will respond to the pull of'spring 86 when the notch85 registers with the end of lever 83, thus permitting the end of said lever to fall into said notch.

Under this condition of operation, the left arm of lever 83 will be moved counterclockwise so that slot 88 will engage the shoulder or step 92 due to the actionof spring on slide 88, spring 95 acting to rotate slide 89 in a counter clockwise direction about shoulder 94 as a pivot. Then, when the high portion of cam -8I again cooperates with the left end oflever 83to rotate lever 83 counterclockwise the slide 89 will be urged leftwardly (as viewed in Fig. 1) to open contact pair 99 and close contact pair NH. The opening of contact pair 99 causes magnet I2 to become deenergized to effect the stopping of shaft 58, as the battery I3| will be cut out of the magnet circuit. The closing of contact IOI completes an energizing circuit for signal lamp I00 (or any other form of alarm) from battery I95 over an obvious circuit through now closed contact pair.I8I. i

The transm-itter remains in its stopped position until slide 89 is released by a push rod I42 which is slidably mounted inbrackets I43-and I44 suitably mounted to the transmitter" frame. A spring I45 surrounding rod I42 normally urges rod I42 rightwardly, out of engagement with slide 89. Rod I42 is provided with'a sidewardly extending pm I 46 which'is normally blocked by a shoulder I41 on a bracket I48. If it is desired to prevent the transmitter from responding to a break signal the push rod I42 is turned to release pin I46 from lug I41 and is positioned sothat pin I46 engages a slot .I49 also in bracket I48.

As previously described, lever I04 is provided with an arm I02 which cooperates withv slide 89. Thus, when rod I42 is depressed tobring pin I46 into engagement with slot I49, said rod I42 will, through the interposition of slide 89 and arm I02, cause lever I04 to rotate clockwise against the action of spring I01, thereby main,-

taining contact pair I09 closed. Manifestly, under this condition of operation, the magnet 81 remains shunted at all times.

Modification esnond n l n e .Qm ihe d i i al a e:

mentswill be described hereinaitenrecoursebe ing had tothe prim ipal embodiment for; a description of the tape sensing and transmitter portion. v Mounted onshaft v58 area pair of cams -I8I and I82, corresponding respectively-to cams 8I and 82 or -the embodiment shown in Fig. 1. Cooperatively associated with cam I8I isone arm I83 of a three-armed lever I84 pivotally mounted on a pivot shaft 185.; Lever I84 is normally;biased in a clockwise direction by aspring I86 to maintain the-cam :follower extremity of arm' I83 in' contactual relation with the, periphery .of cam I8 I. Arm I81 of lever-J84 terminates in an armature portion I88 which; cooperates with a mag;

net I89 suitably mounted in the transmitter apparatus.

. :Lever. [84 1s also provided with an arm I9I, to

i the extremity of which is secured a depending stud I92 which cooperates with a lever I93 also pivotally mounted on pivot. shaft I85. 'Lever I93 isnormally urged in a counterclockwise direction about shaft; I85 bya spring I94. Lever I 93 is provided with a notch I95 which cooperates with arm I96 of, a bell crank lever ;I9' I-pivotally mounted-one, pivot I98. 1 The. other arm I99 of lever I91 cooperateswith a push rod 2 0I, which is slidably mounted in a bracket 202. A spring (a w in Fi .2. {AT ep ndi s u 3 is mounted at the endof the lever I93. and cooperates with alcontact pair 205 included in thecir: cult for the stop magnet". '7 H Associated with cam I82 is a lever 206 pivoted at 201, and which is normally biased in a clockwisedirection by a spring 208 to urgeits clam follower extremity constantly into contac V tual engagement with the periphery of cam I82.

The opposite extremity of lever;206 is provided with a stud 209 which cooperatesiwith' a contact pair ,2 I0. included in the signal line to provide a shunt for the magnet I89.

' Theoperation of the modified form of the present'invention will now be described. Upon the manual closing. of switch 64, the circuit for motor 59 will be completed, thereby tending to When the shaft 53 is inits stop position, as

shown in Fig. 2, the distributor brush '51 is on the stop segment 53 of the'commutator'5I and the signal line circuit is completed from ground through shaft, over conductor I34, through tion-with the principal embodiment of the invention;

In amanner similar to that described in Fig. l, cams I8I and I82 are provided with depressions 22I and 222, respectively, so disposed or related that magnet I89 is energized during substantially the latter half of the stop impulse and short circuited during the remainder of the signal. cycle, for reasons previously mentioned. The timing cam I8I is so designed that should a line .breaki occur, upon the opening of switch 2I1 or otherwise, the code signal being transmitted atthe time of the break will not be mutilated. .In other words, irrespective of when the line .break occurs, the brush arm 51 will always be brought to rest on thestop segment. -While1 shaft 58 is rotating constantly during normal transmission'and the depressionl22l. in

,cam I8I cyclically passes the follower end of arm I83 of lever I84, said end of arm I83 will not'iall into the depression 22I because at that time (which is during the stop period), the ,contactlpair 2I0 opens, due to the coaction between the arm of lever 206 and depression 222 of cam I82, to remove the shunt around magnet I89, thus permitting magnet I89 to energize to hold lever, 484

segment 53,;over" brush 51, through ring 56, over conductor 2 I 3, then either through'the. winding oi, magnet I89 or through the shunting contact pair 2l0f (depending upon the condition of operation, as will presentlyapDear); over line conductor 2I4, through'the receivin magnet 2I5 of remote station 2I6, through switch 2I1, and to grounded battery 218. the'shaft 58 rotates,

code signalsare transmittedover the line cirn tno imonoer already described in connec in its counterclockwise position. .However, if a break. occurs in the line circuit, thus causing the line to be opened, the magnet I89 will not become energized during the stop period, when contact 2I 0 is opened, because battery will no longer be $119- plied thereto from distant station 2 I 6, so that then the lever I84 will respond to the 'pull of spring 186 when the notch 22I registers with the end of lever arm I83, thuspermitting the end of said lever to fall into said notch.

Under this condition of operation, the lever I84 will be actuated in a' clockwise direction so that stud I92 will cause lever I93 to rotate also in a clockwise direction against the action of spring I94 to'effect the disengagement of the end of arm I96 of bell crank lever I91, from the notch in its stopped position untillever I93 is released by ,arm I96 of bell crank I91. This release is effected by depressing the push rod 20I to cause the bell crank I91 to be rotatedcounterclockwise whereby the end of lever arm I96 will again enter the notch I95, permitting the lever I93 to rotate sufliciently in a counterclockwise direction, to

allow contact pair 205 to close.

It is understood, of course, that in the arrangements shown, the magnet I89 could be connected as shown in Fig. 1, or the magnet 81' could be connected as shown in Fig. 2. With the arrangement shown in Fig. 1, the break-lock magnet and/ or its short circuiting contact are in the line circuit only during the stop interval, while in Fig. 2, the break-lock magnet and/or its short circuiting contact are in the line circuit during all of the impulse intervals.

Although certain specific embodiments of the present invention have been shown and described herein, it is to be understood that the invention is not limitedto such embodiments, but is capable of modification, rearrangement, and substitution of parts and elements without departing from the spirit of the invention, and Within the scope of the appended claims.

What is claimed is:

1. In a communication system, a rotary distributor of the start-stop type for generating signals, a break-lock means comprising timing instrumentalities for controlling the operation of said distributor, said means efiective in response to a predetermined condition of the signal line, and means at a remote station for producing said predetermined condition to render said breaklock means effective in timed relation to said signals.

2. In a communication system, a rotary distributor of the start-stop type, a break-lock means for controlling the operation of said distributor, said means effective in response to a predetermined condition of the signal line, cam means for timing the operation of said break-lock means, and means at a remote station for producing said predetermined condition.

3. In a communication system, a rotary distributor of the start-stop type, electromagnetic means for controlling said distributor, said means controlled by a local source of current, a breaklock means for controlling the operation of said electromagnetic means, said break-lock means embodying a magnet normally included in the signal line circuit and effective in response to a predetermined signaling condition, and means at a remote station for producing said predetermined signaling condition.

4. In a communication system, a rotary distributor of the start-stop type, electromagnetic means for controlling said distributor, said means controlled by a local source of current, a breaklock means for controlling the operation of said electromagnetic means, said break-lock means comprising a magnet normally included in the signal line circuit and effective in response to a predetermined signaling condition, cam means for timing the operation of said break-lock means, and means at a remote station for producing said predetermined signaling condition.

5. In a control device, signal generating means, electromagnetic means for controlling said signal generating means, said electromagnetic means controlled by a local source of current, means included in the signal line circuit and effective in response to a predetermined signaling condition, lever means controlled by said last recited means for controlling the effectiveness of said electromagnetic means, and cam means for timing the operation of said lever means.

6. In a communication system, a rotary distributor of the start-stop type, electromagnetic means for controlling said distributor, said means controlled by a local source of current, a breaklock means for controlling the operation of said electromagnetic means, said break-lock means comprising a magnet normally included in the signal line circuit and effective in response to a predetermined signaling condition, means for normally shunting the circuit through said magnet, cam means for timing the operation of said shunting means to render said break-lock means effective to stop said distributor, and means at a remote station for producing said predetermined condition.

"I. In a control device, signal generating means,

cam means for timing the operation of said shunting means to render said break-lock means effective to stop said distributor.

8. In a communication system, a rotary distributor ofthe start-stop type, electromagnetic means for controlling said distributor, said means controlled by a local source of current, a breaklock means for controlling the operation of said electromagnetic means, said break-lock means including a magnet normallyinserted in the signal line circuit and effective in response to a predetermined signaling condition, means at a remote station for producing said predetermined condition, and means to render said brake-lock means ineffective.

. 9. .In a communication system, a segmental distributor of the start-stop type for transmitting signals comprising a predetermined number of signal impulse intervals, electromagnetic means for controlling said distributor, said means controlled by a local source of current, a break-lock means for controlling the operation of said electromagnetic means, said break-lock means comprising a magnet normally connected to one only of the segments of said distributor and effective in response to the connection of said segment to the line pursuant to a predetermined signaling condition, cam means for-timing the operation of said break-lock means, and means at a remote station for producing said predetermined condition.

10. In a communication system, -a rotary distributor having a start segment, a stop segment and a plurality of code segments, a brush associated with'said distributor, means for rotating said brush, a break-lock means for controlling the operation of said distributor, means for conditioning said break-lock means as said brush traverses said stop, start, or code segments of said distributor, and means to permit the operation of said conditioned break-lock means only when said brush arm is on said stop segment.

11. In a communication system, a rotary distributor of the start-stop type, electromagnetic means for controlling said distributor, said means controlled by a local source of current, a break-lock means for controlling the operation of said distributor, said break-lock means including a magnet normally inserted in-the signal line circuit and effective in response to a predetermined signaling condition, means at a remote station for producing said predetermined condition, cam means for timing the period of efiectiveness of said remote means to render said break-lock means eifective to stop said distributive.

WALTER J. ZENNER. 

